for/in

'for' is setting up a loop. If you have ever done programming before, the concept is the same. Say you have a python list:

fab_four = ['george', 'paul', 'john', 'ringo']

now you can set up a loop with your 'for/in' statement like:

for beatle in fab_four

which will then loop through all the members in that list and effectively assign the variable name 'beatle' to whatever is in the list for each iteration. iteration 1 will yield, beatle = 'george', iteration 2 will be beatle = 'paul', etc... until all members of the list are exhausted at which point the loop will end and any statements that appear after the for loop will be implemented.

If you, for example, wrote

fab_four = ['george', 'paul', 'john', 'ringo']
for beatle in fab_four:
    print(beatle)

the result would be

'george'
'paul'
'john'
'ringo'

because the print statement is using the argument 'beatle' every time the for loop iterates.

does that make sense?